If you want to get your crush’s attention, try and really figure out what they are putting out in the world. Usually, whatever they are putting out in the world is what they need from others.
If they enjoy heated discussions or debates, they probably desire someone they can have a mental connection with. Ask them what they think about a certain subject and give them the chance to engage with you over some topic that matters to them.
If they spend most of their time caring for others, they might be longing for someone to care for them. Do something kind for them like buy their favorite drink out of the vending machine and tell them the machine gave you the wrong one but you noticed them drinking it before. That also lets them know in a subtle way that you pay attention to them.
If they are always trying to make sure people are comfortable they probably need someone else to make them comfortable. How are they comforting others? Do that for them. You’d be surprised at how easy it might be to talk to them once they feel comfortable with you.
If they enjoy humor, send memes.
If they love music, share a favorite song.
If they check up on people, check up on them.
If they volunteer, see how you can help.
Recognize what they do and who they are.
Get to know them. You don’t have to approach them and confess your undying love. That looks a little selfish anyway if you haven’t even taken the time to really know them. Know them as a person and a friend and let them know you see them and they matter. You may get to know them and realize they aren’t really your cup of tea. You may discover you really connect and relate to them. Take the pressure off and just try to be a friend. If they reject friendship, even casual friendship, they aren’t really your person anyhow.